Ipomoea species are members of the morning glory family Convolvulaceae. Ipomoea batatas, the cultivated species, is commonly produced for consumption and referred to as the white or yellow sweetpotato and the orange yam. The plants are typically fast growing, green vines possessing a wide variety of leaf shapes ranging from palmate and deeply lobed, to cordate or triangular shaped leaves with no lobes. Ornamental sweetpotates, which have been bred and selected for their unique foliage colors, leaf shapes and plant habits, typically do not produce large fleshy storage roots like the sweetpotato cultivated for consumption. In comparison, storage roots produced by ornamental sweetpotates are typically not as large because no selection has been exercised for yield, thus storage roots do not begin to swell until very late in the season. Further, the few storage roots that are formed by ornamental sweetpotatoes are typically not as attractive as those produced by the tablestock types as they are generally cracked, very malformed, often mottled in skin and flesh color, and are not palatable.
Late in the growing season when day-lengths begin to shorten or when the plants are stressed, ornamental sweetpotato plants produce tubular flowers that are similar to morning glories, but most plantings are dominated by the appearance of the foliage. The plants are highly desirable due to their ability to grow under varied stress conditions, cover a large space, and last the entire growing season. Moreover, these plants have few insect or disease problems.
Until the release of the Sweet Caroline series of ornamental sweet potatoes (see below) there were six popular types of Ipomoea batatas ornamental sweetpotates being cultivated primarily for their annual, summer vines in landscaping applications. These six cultivars are: ‘Blackie’ (not patented), having purple foliage and lavender flowers; ‘Terrace Lime’ (not patented) and ‘Margarita’ (not patented; also known as ‘Sulfur’), which have large brilliant chartreuse leaves and lavender blooms; ‘Black Heart’ (not patented; also known as ‘Ace of Spaces’), having heart-shaped leaves with burgundy purple color; ‘Tricolor’ (not patented; also known as ‘Pink Frost’), a variegated plant having plate green, white, and pink-margined leaves; and ‘Lady Fingers’ (unpatented), which has medium green, dainty leaves divided into long, thin, fingerlike lobes that are complemented by burgundy stems and veins.
Ipomoea batatas ‘Margarita’ was recently been released in the United States, and has become widely used as a landscape annual. However, it is not suitable for mixed containers as this variety exhibits a very vigorous growth and tends to out-compete other species. See Armitage. A. M. and J. M. Garner, (2001) Ipomoea batatas ‘Margarita’. HortScience 36:178. Another popular variety, ‘Blackie’, is a vigorous purple-leaved clone, which is also unsuited to containerized gardens.
Therefore, to meet the current horticultural demand, it is desirable to produce new, more robust cultivars of ornamental sweetpotato with attractive foliage colors, leaf shapes, and plant architectures. In addition, it would be advantageous to develop cultivars of ornamental sweetpotato exhibiting a more compact growth, and which do not out-compete other species in mixed containers.
Ipomoea batatas ‘Sweet Caroline Light Green’ (U.S. Plant Pat. No. 15,028, issued Jul. 20, 2004), ‘Sweet Caroline Green’ (U.S. Plant Pat. No. 15,056, issued Aug. 3, 2004), ‘Sweet Caroline Bronze’ (U.S. Plant Pat. No. 15,437, issued Dec. 21, 2004), ‘Sweet Caroline Purple’ (U.S. Plant Pat. No. 14,912, issued Jun. 15, 2004), and ‘Sweet Caroline Red’ (U.S. Plant Pat. No. 17,483, issued Mar. 13, 2007) are recently introduced cultivars developed at North Caroline State University that are characterized by compact growth habit, moderate to deeply lobed palmate leaves, and attractive foliage color.
The present invention relates to a new and distinct variety of Ipomoea batatas named ‘Sweet Caroline Sweetheart Light Green’. ‘Sweet Caroline Sweetheart Light Green’ is a very compact to compact, partially mounded variety producing many shoots and having dense foliage. This variety is distinguishable from other varieties by its small, heart-shaped, light green to chartreuse colored leaves and erect to semi-erect architecture. The plant has good vigor, is very well branched, and has thin stems that tend to intertwine. It is much less vigorous than Ipomoea batatas ‘Margarita’ and ‘Blackie’ and is well suited for container production.
Lineage. The Ipomoea batatas ‘Sweet Caroline Sweetheart Light Green’ cultivar (breeding designation NC779-23NORN) originated from a conventional cross between Ipomoea batatas cultivars NC7-1ORN (the female parent; not patented) and NC146-1ORN (the male parent; not patented) conducted during October 2001 to April 2002 at Raleigh, N.C.
NC7-1ORN was selected from seed obtained from the selfing of ‘Sulfur’. NC146-1ORN resulted from a cross between ‘Sulfur’ (the female parent) and the clone ‘S×BLR7-2’ (the male parent; not patented). ‘S×BLR7-2’ was derived from a cross between ‘Sulfur’ (the female parent) and ‘Blackie’ (the male parent). Seed from this cross were planted in the Horticultural Greenhouses in Spring 2002. The single, individual plant now known as Ipomoea batatas ‘Sweet Caroline Sweetheart Light Green’ was selected in August and September 2002 because of its combination of exceptional features, and has been propagated asexually since that time.
Asexual Reproduction. Since its selection, Ipomoea batatas ‘Sweet Caroline Sweetheart Light Green’ has been asexually reproduced at Raleigh, N.C., predominantly by vegetative propagation of vine cuttings. Successively, there have been three cycles of vegetative propagation, one cycle of tissue culture micropropagation, and multiple vegetative propagation cycles to increase the plant population. Asexual reproduction of the new Ornamental Sweetpotato cultivar by cuttings has shown that the unique features of the new cultivar are stable and the plant reproduces true to type in successive generations of asexual reproduction.